OKLAHOMA CITY – Time to fire up some Bee Gees and a little "Stayin’ Alive" (Google or YouTube it, kids) and dedicate it to the Missouri Tigers.

Faced with winning the Phillips 66 Big 12 Baseball Championship and the automatic bid in order to earn a spot in the NCAA Tournament, the eighth-seeded Tigers became the only undefeated squad in the four-team Division One pool. Missouri recorded its Big 12-best fifth walk off victory with a 5-4 win over Oklahoma State Thursday.

The Tigers (26-30) earned a day off and won’t play again until 9 a.m. Saturday. The Cowboys (35-22) dropped into the loser’s bracket and will face Texas at 3:15 pm Friday. The winner will face Missouri while the loser goes home.

"We’ve had some great ninth-inning wins and extra-inning wins, and today is probably one of the biggest ones we’ve had all year just because we need to win this tournament," Missouri’s Eric Garcia said. "I feel like we’re getting our confidence right now."

Garcia was mobbed by his teammates after his one-out single to right in the bottom of the ninth provided the winning tally. Second baseman Andrew Thigpen, who came into the game hitting .130, led off the ninth with a single. Conner Mach tried to sacrifice but then singled on an 0-2 pitch. After another sacrifice resulted in a fielder’s choice, Garcia came through with the game winner.

Thigpen also started Missouri’s five-run fifth inning with a leadoff single. The Tigers took advantage of three walks by Cowboys closer Chris Marlowe who faced three hitters and failed to get an out.

"At the juncture that I put Chris (Marlowe) in, it didn't look like we were going to score very many," Oklahoma State coach Frank Anderson said. "I wanted to put him in to strike two guys out and it didn't work out."

The Cowboys had a runner picked off in the first inning and lost another runner in a rundown in the fifth inning. Missouri starter Rob Zastryzny tiptoed through a mine field working seven innings.

"The last time I pitched against them, they were really aggressive to fastballs, so I wanted to be able to throw off-speed for first pitch and mix everything in, and I think I was able to do that pretty well," Zastryzny said.

Zastryzny left with two runners aboard in the eighth inning and no outs. Big 12 newcomer of the year Zach Johnson jacked the first pitch from reliever Dusty Ross for a three-run homer.

In the top of the ninth, Johnson came through with a two-out single through the left side to tie the game at 5-all and set up Missouri’s walk-off heroics.

"I’m really proud of these guys, not just this weekend, but the last five or six weeks," Missouri coach Tim Jamieson said. "They know we have to finish above .500 (to be eligible for an at-large NCAA bid) or win the tournament. We can’t finish above .500, so it’s pretty simple math."